The present invention relates to a method and apparatus for accessing an audio memory, and more particularly, to a method and apparatus for pre-caching non-audio related data in the audio memory of a video game system.
Many of us have seen films containing remarkably realistic dinosaurs, aliens, animated toys and other fanciful creatures. Such animations are made possible by computer graphics. Using such techniques, a computer graphics artist can specify how each object should look and how it should change in appearance over time, and a computer then models the objects and displays them on a display such as your television or a computer screen. The computer takes care of performing the many tasks required to make sure that each part of the displayed image is colored and shaped just right based on the position and orientation of each object in a scene, the direction in which light seems to strike each object, the surface texture of each object, and other factors.
Because computer graphics generation is complex, computer-generated three-dimensional graphics just a few years ago were mostly limited to expensive specialized flight simulators, high-end graphics workstations and supercomputers. The public saw some of the images generated by these computer systems in movies and expensive television advertisements, but most of us couldn""t actually interact with the computers doing the graphics generation. All this has changed with the availability of relatively inexpensive 3D graphics platforms such as, for example, the Nintendo 64(copyright) and various 3D graphics cards now available for personal computers. It is now possible to interact with exciting 3D animations and simulations on relatively inexpensive computer graphics systems in your home or office.
Interactive 3D computer graphics systems are often used to play video games. The xe2x80x9cgaming experiencexe2x80x9d however typically involves more than just video content. For example, almost all gaming experiences involve audio content that accompanies the video content. The audio system described herein enables sound emitters to be placed in three-dimensional space and provides a powerful means of generating psycho-acoustic 3D sound effects with a pair of speakers. The audio system includes an audio memory that is usable, for example, to store sound samples, instrument wave tables, audio tracks and the like read from a mass storage device such as a DVD. The samples, wave tables, tracks, etc. are subsequently read out and processed by an audio digital signal processor to produce the game audio content. This content is transferred to a main memory from where it is subsequently read out for supply to a decoder and output to speakers. The separate audio memory improves the access for the audio processing circuitry to audio data by avoiding the need to contend with other resources (e.g., the graphics subsystem) attempting to access the main system memory.
As further described herein, the provision of a separate audio memory also provides an opportunity to further enhance the system""s ability to efficiently provide access to data to resources that need such access. For example, a DVD has a relatively high xe2x80x9clatencyxe2x80x9d, i.e., it takes a relatively long time for data to be returned responsive to a request for the data. Therefore, it is useful to pre-fetch data such as animation data and compressed graphics data from the DVD prior to the time that the data is needed so that the data can be quickly provided to a component needing the data. The audio memory may be used as a cache for this xe2x80x9cpre-fetchedxe2x80x9d non-audio-related data. Then, when the data is needed, for example in the rendering pipeline, a DMA circuit is used to transfer the data to a main memory where it becomes available to the component that needs it. The data transferred to the main memory may be decompressed, if appropriate.
Thus, in accordance with one aspect of the present invention, a video game system includes an audio digital signal processor, a main memory and an audio memory separate from the main memory and storing audio-related data for processing by the audio digital signal processor. Memory access circuitry reads non-audio-related data stored on a mass storage device and writes the non-audio-related data to the audio memory. The non-audio-related data is later read from the audio memory and written to the main memory without being processed by the audio digital signal processor.
In accordance with another aspect of the present invention, a method of accessing non-audio-related data stored on a mass storage device includes providing an audio memory separate from a main memory and storing therein audio-related data for processing by an audio digital signal processor. Non-audio related data is read from the mass storage device and written to the audio memory. The non-audio-related data is later read from the audio memory and written to a main memory without being processed by the audio digital signal processor.